| Message ID | 1467284899-22575-1-git-send-email-pl@kamp.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 30/06/2016 13:08, Peter Lieven wrote: > this fills up the allocationmap at iscsi_open. This helps > to reduce the number of get_block_status requests during runtime > significantly. > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > block/iscsi.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/block/iscsi.c b/block/iscsi.c > index 0cdcedb..04fb0a3 100644 > --- a/block/iscsi.c > +++ b/block/iscsi.c > @@ -1774,6 +1774,22 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, > iscsilun->block_size) >> BDRV_SECTOR_BITS; > if (iscsilun->lbprz) { > ret = iscsi_allocmap_init(iscsilun, bs->open_flags); > + if (ret == 0) { > + unsigned int max_reqs = 64; > + int64_t sector_num = 0; > + while (max_reqs-- && sector_num < bs->total_sectors) { > + int n; > + BlockDriverState *file; > + ret = bdrv_get_block_status(bs, sector_num, > + BDRV_REQUEST_MAX_SECTORS, > + &n, &file); > + if (ret < 0) { > + break; > + } > + sector_num += n; > + ret = 0; > + } > + } > } > } > > This can take a long time and the disks may not even be ever used. I don't think it's a good idea. Paolo
Am 30.06.2016 um 17:59 schrieb Paolo Bonzini: > > On 30/06/2016 13:08, Peter Lieven wrote: >> this fills up the allocationmap at iscsi_open. This helps >> to reduce the number of get_block_status requests during runtime >> significantly. >> >> Signed-off-by: Peter Lieven <pl@kamp.de> >> --- >> block/iscsi.c | 16 ++++++++++++++++ >> 1 file changed, 16 insertions(+) >> >> diff --git a/block/iscsi.c b/block/iscsi.c >> index 0cdcedb..04fb0a3 100644 >> --- a/block/iscsi.c >> +++ b/block/iscsi.c >> @@ -1774,6 +1774,22 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, >> iscsilun->block_size) >> BDRV_SECTOR_BITS; >> if (iscsilun->lbprz) { >> ret = iscsi_allocmap_init(iscsilun, bs->open_flags); >> + if (ret == 0) { >> + unsigned int max_reqs = 64; >> + int64_t sector_num = 0; >> + while (max_reqs-- && sector_num < bs->total_sectors) { >> + int n; >> + BlockDriverState *file; >> + ret = bdrv_get_block_status(bs, sector_num, >> + BDRV_REQUEST_MAX_SECTORS, >> + &n, &file); >> + if (ret < 0) { >> + break; >> + } >> + sector_num += n; >> + ret = 0; >> + } >> + } >> } >> } >> >> > This can take a long time and the disks may not even be ever used. I > don't think it's a good idea. Sure, the target might stay unused, but why do you suspect its slow? Peter
On 07/07/2016 13:40, Peter Lieven wrote: >>> >> This can take a long time and the disks may not even be ever used. I >> don't think it's a good idea. > > Sure, the target might stay unused, but why do you suspect its slow? I don't suspect it's slow; it's just that it can be O(size of disk), and can send really a lot of commands down the link. I don't think it's a good thing to do in advance. Paolo
diff --git a/block/iscsi.c b/block/iscsi.c index 0cdcedb..04fb0a3 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -1774,6 +1774,22 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags, iscsilun->block_size) >> BDRV_SECTOR_BITS; if (iscsilun->lbprz) { ret = iscsi_allocmap_init(iscsilun, bs->open_flags); + if (ret == 0) { + unsigned int max_reqs = 64; + int64_t sector_num = 0; + while (max_reqs-- && sector_num < bs->total_sectors) { + int n; + BlockDriverState *file; + ret = bdrv_get_block_status(bs, sector_num, + BDRV_REQUEST_MAX_SECTORS, + &n, &file); + if (ret < 0) { + break; + } + sector_num += n; + ret = 0; + } + } } }
this fills up the allocationmap at iscsi_open. This helps to reduce the number of get_block_status requests during runtime significantly. Signed-off-by: Peter Lieven <pl@kamp.de> --- block/iscsi.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)